In all things of nature there is something of the marvelous– Aristotle
Late May and June is the time we most commonly encounter the native giant silkworm and other Saturnidae family moths here in Connecticut. Most of these moths are fairly large and can cause excitement when seen. They can often be found early in the morning clinging to the windows or walls of buildings where lights were on at night. The moths will flutter clumsily on the ground when near death. Do not worry about trying to feed them something because these moths have vestigial mouthparts and cannot feed. They emerge from their cocoons in late spring, generally mate quickly, and then die after completing their procreative life’s work.
The caterpillars of certain species can be huge, depending upon species, with some, like those of the cecropia, almost becoming the size of an Oscar Mayer wiener. Many have knobs and colorful markings. The caterpillars can consume a large amount of foliage before pupating, especially if a large amount of eggs are laid on a single plant. The orange striped oakworm is considered a pest for this reason and is more prevalent in the eastern part of Connecticut, especially, in the past, in Windham County.
Most Saturniid caterpillars feed on foliage of woody plants, and some are particular to the host plants they are found on. The Promethea, for example are especially found on black cherry, spicebush and sassafras, and tulip tree. Orange-striped oakworms are mostly found on oaks, with a strong preference for red oaks, in my experience. I have found Polyphemus the majority of times on maples, but they do feed on birch, willow and rose family plants as well.
Most silkworm and royal moth caterpillars reach maturity from June onward to November, depending upon species. Giant silkworm caterpillars often tie leaves of the host plant together and spin a cocoon inside where they pupate. Promethea attach this leaf structure to twigs of the host plant, which are easy to spot as they dangle down for the winter. Other silkworms may or may not attach the leaf structure to the host plant. Cecropias, for example, may attach the structure horizontally on branch undersides, or they may drop to the ground and form one there.
The subfamily Ceratocampinaeincludesthe Spingicampa bicolor whose caterpillar feeds on honey locust and Kentucky coffee tree. This is a spectacular caterpillar which is sometimes mistaken for a hornworm.
This subfamily also includes green-striped mapleworms Dryocampa rubicunda, and the notorious orange-striped oakworm Anisota senatoria. The moth of the mapleworm is the colorful rosy maple moth. Both species can sometimes be pests and severely defoliate the host plants.
The subfamily Hemileucine includes the beautiful Io moth Automeris io. Male and female moths are vastly different in color and markings, with the female having spectacular eyespots on the hindwings. Caterpillars have stinging barbs whose sting is similar to, but more painful than, that of stinging nettles and are gregarious in early instars.
The giant silkworm moths are in the subfamily Saturniinae. This family includes the beautiful luna moth Actias luna, a favorite of many people who otherwise have no interest in moths, or even insects in general. This moth has a beautiful green color and long tails on the hindwings. Other members of this subfamily include the promethea, Cecropia, polyphemus and calleta.
Antheraea polyphemus moths have large eyespots that appear as blue cylinders on the hindwings. The centers of eyespots on both wings have no scales and are see-through. Late instar caterpillars have white setal bases that can gleam silver in the sunlight. Caterpillars are also very plump and they are similar to those of the luna moth.
The most spectacular caterpillar of the giant silkworm moths is that of the Cecropia Hyalophora cecropia. Later instar caterpillars have colorful knobs, and their large size-up to 10 cm., just makes them more dramatic. They can get so heavy that the lower branches they are on bend almost to the ground. This native moth is the largest in North America.
Many of our Saturniidae caterpillars, especially the giant silkworms, fall victim to the parasitic tachinid fly, a non-native parasite which was introduced, without much scientific insight apparently, to control the spongy (gypsy) moth. According to UConn’s Dr. David Wagner, a study (Boettner et al) in 2000 showed an 82 % parasitism rate on 1,400 Cecropia released in a Massachusetts forest.
Let us end on a positive note, though. Of the many caterpillars of the Saturnidae caterpillars I have found and raised (and later released where originally found), only a handful suffered from parasitism. And on returns to the same areas, caterpillars or moths are still very much present. So rather than being a limpid herald of doom, I should ponder the fact that sometimes nature responds well to any unnatural interferences. That is my experience, for the most part. Life does go on, but perhaps must do so somewhere else.
Life continues in lots of places, and life is a magical thing.
- Laurel Clark, NASA astronaut
Pamm Cooper
Uconnladybug's Blog 
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